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diff --git a/files/zh-cn/web/javascript/reference/global_objects/map/keys/index.html b/files/zh-cn/web/javascript/reference/global_objects/map/keys/index.html new file mode 100644 index 0000000000..59c1b50654 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/map/keys/index.html @@ -0,0 +1,80 @@ +--- +title: Map.prototype.keys() +slug: Web/JavaScript/Reference/Global_Objects/Map/keys +tags: + - ECMAScript 2015 + - Iterator + - JavaScript + - Map + - Method + - Prototype +translation_of: Web/JavaScript/Reference/Global_Objects/Map/keys +original_slug: Web/JavaScript/Reference/Global_Objects/Map/keys +browser-compat: javascript.builtins.Map.keys +--- +<div>{{JSRef}}</div> + +<p><code><strong>keys()</strong></code> 返回一个引用的 <code><strong>Iterator</strong></code> 对象。它包含按照顺序插入 <code>Map</code> 对象中每个元素的key值。</p> + +<div>{{EmbedInteractiveExample("pages/js/map-prototype-keys.html")}}</div> + + + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox notranslate"><code><em>myMap</em>.keys()</code></pre> + +<h3 id="返回值">返回值</h3> + +<p>一个存在引用关系的 {{jsxref("Map")}} iterator 对象.</p> + +<h2 id="例子">例子</h2> + +<h3 id="使用_keys">使用 <code>keys()</code></h3> + +<pre class="brush:js notranslate">var myMap = new Map(); +myMap.set("0", "foo"); +myMap.set(1, "bar"); +myMap.set({}, "baz"); + +var mapIter = myMap.keys(); + +console.log(mapIter.next().value); // "0" +console.log(mapIter.next().value); // 1 +console.log(mapIter.next().value); // Object +</pre> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">规范</th> + <th scope="col">状态</th> + <th scope="col">备注</th> + </tr> + <tr> + <td>{{SpecName('ES2015', '#sec-map.prototype.keys', 'Map.prototype.keys')}}</td> + <td>{{Spec2('ES2015')}}</td> + <td>Initial definition.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-map.prototype.keys', 'Map.prototype.keys')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + + + +<p>{{Compat("javascript.builtins.Map.keys")}}</p> + +<h2 id="参见">参见</h2> + +<ul> + <li>{{jsxref("Map.prototype.entries()")}}</li> + <li>{{jsxref("Map.prototype.values()")}}</li> +</ul> |